This invention relates to metals having insoluble materials distributed therein, and particularly to a convenient method for adding insoluble materials to a liquid or partially liquid metal.
Solid insoluble materials are commonly added to at least partially liquid metals to provide desirable characteristics to the solidified product obtained therefrom. For example, solid materials which are softer than the metal are added to provide desirable characteristics to the solidified product thereof when it is used as a bearing. Likewise, materials which are harder than the metal are added to extend the life of the solidified product thereof when it is subjected to extreme friction forces. However, it is difficult to add more than about 3 weight percent of an insoluble material to a liquid or partially liquid metal because the insoluble material is generally rejected by the metal and either floats to the surface or sinks to the bottom thereof. Severe and lengthy agitation is generally required to distribute the material into the liquid or partially liquid metal. This distribution method is time consuming and is limited to the addition of relatively small amounts of insoluble material to a metal.
Methods have recently been developed by which up to about 30 weight percent of an insoluble material may be blended with an at least partially liquid metal. These methods are described in U.S. Pat. Nos. 3,948,650; 3,951,651; and 4,174,214. These methods require careful temperature control, special melting equipment and special agitation equipment. Such equipment is expensive and not always readily available at some locations.
A method to easily distribute insoluble material into a liquid or partially liquid metal without the need of severe and lengthy agitation would be desirable. The invention provides such a method.